Chapter 6 Atoms & their interactions

Ch 6: The Chemistry of LifeCh 6: The Chemistry of Life

6.1 - Atoms and Their Interactions

6.1 - Atoms and Their Interactions

Section 6.1Section 6.1

What is an Element?

What are Atoms?

2 Types of Chemical Bonds

Chemical Reactions

Inside This Section...Inside This Section...

A substance that can not be broken down into smaller particles.

90 elements naturally occur on earth

25 are essential to living things

Each element is identified by a symbol

What is an Element?What is an Element?


ElementsElements


C = CarbonCa = Calcium

Na = Sodium

ElementsElements


K = Potassium

N = Nitrogen

Fe = Iron

ElementsElements


AU = Gold

Elements that are present in small amounts in the human body.

N,K,Ca, and Fe are a few examples

Help control cell metabolism

Plants obtain trace elements through their roots while animals obtain trace elements through what they eat.

Trace ElementsTrace Elements


The smallest part of an element that still maintains all the characteristics of that element.

The basic building blocks of all matter

What is an Atom?What is an Atom?


Nucleus: Center of the Atom

Electrons:

The outer particles

Negatively charged

Protons:

Particles found in the nucleus

Positively charged

Neutrons: Particles found in the nucleus that have no charge.





Electron (-)

Proton (+)

Neutron (0)

Electron and Proton numbers are always the same

Energy LevelsEnergy Levels


Regions around the nucleus that the electrons travel.Atoms like to have their outer most energy level full.

Energy Levels & ElectronsEnergy Levels & Electrons


Energy LevelEnergy Level # of # of ElectronsElectrons

1 2

2 8

3 18

Atoms of the same element that have different numbers of neutrons.

What are Isotopes?What are Isotopes?


Most carbon nuclei contain six neutrons

Some have 7 or 8

These three atoms are isotopes

We refer to the isotopes in terms of the combined total of protons and neutrons

Carbon-12 has 6 protons and 6 neutrons

How many protons and neutrons does carbon-13 and carbon-14 have??

What are Isotopes?What are Isotopes?


Read Problem Solving Lab 6.1 in groups of twos (pg 149)

Answer the 4 questions

Problem Solving Lab 6.1Problem Solving Lab 6.1


A substance that is composed of two or more different elements that are chemically combined.

Properties of compounds are different than those of their individual elements. (NaCl)

Compounds can always be described with an equation. (H20)

CompoundsCompounds


When two elements share electrons in their outer energy level.

Atoms are the happiest when their outer energy level is full.

Water is an example

Bond #1: Covalent BondsBond #1: Covalent Bonds


A bond between atoms that is formed by losing and gaining an electron.

NaCl is an example

Na has one electron in its outer shell

Cl has 7 in its outer shell

The two oppositely charged atoms now attract each other like magnets.

Bond #2: Ionic BondBond #2: Ionic Bond


Chemical reactions occur when bonds between compounds are broken or formed.

Chemical reactions must have the right environment

pH

Temperature

Energy

Concentration

Chemical ReactionsChemical Reactions


Reactant + reactant --> Product

Reactants undergo chemical reactions

Products are formed in chemical reactions

2H2 + O2 --> 2H2O

Key Point: atoms are never created or destroyed

Chemical EquationsChemical Equations


All of the chemical reactions that occur in the human body.

Produce energy

Require energy

Build necessary molecules for bodily functions

MetabolismMetabolism


Solution: A mixture in which one or more substances are evenly distributed in another substance.

Salt Water

Kool-Aid

Solutions and MixturesSolutions and Mixtures


Mixture: A combination of substances in which the individual components retain their chemical properties.Sand and Salt

pH is a measure of how acidic or basic a substance is.

Scale of 0-14

pH paper is used to determine the pH level

A pH below 7 is acidic

A pH above 7 is basic

A pH of 7 is neutral (Water)

pH LevelspH Levels


pH LevelspH Levels


Any substance that forms hydrogen ions in water.

H+

When HCl is put into water H+ and Cl- ions.

AcidAcid


Any substance that forms hydroxide ions in water.

OH-

When NaOH is put in water you get Na+ and OH- ions.

BaseBase


Acids

Orange Juice

Stomach Acids

Tomato Juice

Common Acids and BasesCommon Acids and Bases


Bases

Toothpaste

Baking Powder

Chlorine Bleach


What is an Element?

What are Atoms?

2 Types of Chemical Bonds

Chemical Reactions

In Review...In Review...


What are some characteristics of water?

How do organisms use water to live and grow?

Jump StartJump Start


6.2 - Water and Diffusion

6.2 - Water and Diffusion


The Importance of Water

The Characteristics of Water

Bond #3: Hydrogen Bonds

Diffusion


Most life processes occur only in water

Helps to transport materials in organism

70 to 95% of most organisms is Water

The Importance of WaterThe Importance of Water


Water is polar

Water sticks but isn’t sticky

Capillary action: able to creep up thin tubes

Water resists temperature changes

Water expands when it freezes

The Characteristics of WaterThe Characteristics of Water


Water (H2O) contains two hydrogen atoms and one Oxygen atom that are covalently bonded to each other

The Shared electrons are more attracted to the Oxygen atom than to the hydrogen atoms (Unequal sharing)

Results in a polar molecule: It has a positive and a negative end

Polar likes polar (i.e. Ionic compounds like salt and other polar molecules like sugar)

Water is PolarWater is Polar


Because water molecules have a positive end and a negative end, there will be an attraction between water molecules

This results in Hydrogen Bonds between the oxygen atom of one molecule and the hydrogen atom of another

Weaker Bond

Bond #3: Hydrogen BondsBond #3: Hydrogen Bonds


It takes a lot of energy to increase its temperature

Loses a lot of heat when it cools

These features help maintain a steady environment (i.e. in cells)

What Resists Temperature ChangeWhat Resists Temperature Change


Ice Floats - less dense

What would happen to lake Michigan if ice was more dense than water?

Water expands when it freezesWater expands when it freezes


Anything that is moving has kinetic energy

If you look at the molecules of gasses, liquids and some solid molecules under a very powerful microscope, you will see that they are randomly moving --> Brownian motion

Brownian MotionBrownian Motion


Diffusion: The net movement of particles from an area of higher concentration to an area of lower concentration.

A very slow process --> Relies on random molecular motion (Brownian motion)

Affected by 3 factors

Concentration (most important factor)

Temperature

Pressure

DiffusionDiffusion


DiffusionDiffusion


Diffusion continues until the two substances are distributed evenly --> Dynamic Equilibrium

Concentration gradient: the difference in concentration of a substance across space.

At dynamic equilibrium, there is no concentration gradient

DiffusionDiffusion



The Importance of Water

The Characteristics of Water

Bond #3: Hydrogen Bonds

Diffusion



6.3 - Life Substances6.3 - Life Substances


The Structure of Carbon

Carbohydrates

Lipids

Proteins

Nucleic Acids


Carbon has 4 electrons in its outer energy level

Can form 4 covalent bonds with other elements

Can also bond with other carbon atoms

CarbonCarbon


CC

3 types of bonds:

Single bond: each atom shares 1 electron

Double bond: each atom shares 2 electrons

Triple bond: each atom shares 3 electrons

CarbonCarbon


CC

CarbonCarbon


CC CC

C C

CarbonCarbon


CC CC

C C

Carbon atoms can form straight chains, branched chains, or rings and can bind to other elements

Can form a whole bunch of carbon structures

CarbonCarbon


CC

Water - H2O

Glucose - C6H12O6

Isomers: Same simple formula but different 3D structure

Glucose and Galactose are both C6H12O6

Simple FormulasSimple Formulas


Large molecules are called macromolecules (e.g. proteins)

Macromolecules are formed by binding together smaller molecules into chains (Polymer)

Molecular ChainsMolecular Chains


Condensation: Chemical reaction by which polymers are formed (water is removed)

Hydrolysis: Chemical reaction by which polymers are broken apart (water is used)

Condensation and HydrolysisCondensation and Hydrolysis


Organic compound composed of Carbon, hydrogen and oxygen.

2 H’s and 1 O for every carbon

Simplest type is monosaccharides like glucose and fructose.

CarbohydratesCarbohydrates


Two monosaccharides bind to form a disaccharide (i.e. Sucrose = glucose + fructose)

Many monosaccharides bind to form polysaccharides (i.e. starch and cellulose - glucose polymers)

CarbohydratesCarbohydrates



monosaccharide (glucose)

disaccharide (sucrose)

polysaccharide (starch)

Lipids are fats and oils.

Organic compound with a large proportion of C-H bonds and less oxygen than carbohydrates.

Nonpolar

Used in cells for energy storage, insulation and protection.

LipidsLipids


Most commonly 3 fatty acids bound to a glycerol molecule. (pg 164)

LipidsLipids


Provide structure for tissues and organs

Carry out cell metabolism

Large, complex polymer made of Carbon, hydrogen, oxygen, nitrogen and usually sulfur.

Building blocks are various combinations of amino acids

Amino acids join together with peptide bond

ProteinsProteins


An Enzyme is a protein that changes the rate of a chemical reaction

Involved in almost all metabolic processes.

Speed up chemical reactions

ProteinsProteins


Stores cellular information in the form of a code.

Polymer of smaller subunits called nucleotides.

Nucleotides consist of C, H, O, N, P atoms.

Nucleotides make up our DNA

Nucleic AcidsNucleic Acids


Nucleic acids have 3 parts:

A Base

A Simple sugar

A Phosphate group



NitrogenouNitrogenous Bases BasePhospPhosp

hatehateO

SugSugarar

O



NitrogenouNitrogenous Bases BasePhospPhosp

hatehateO

SugSugarar

O


The Structure of Carbon

Carbohydrates

Lipids

Proteins

Nucleic Acids


Technology

Chapter 6 Atoms & their interactions